What gas is used in supermarkets to hasten avocado ripening?

“Supermarkets use ethylene gas to hasten avocado ripening.”

Avocados are climacteric fruits: they mature on the tree but generally ripen after harvest. Commercial fruit is often picked hard and green, kept cool during transport, and treated with synthetic ethylene before sale. The gas accelerates the natural ripening process so stores can offer fruit that is ready to eat or close to it.

At room temperature, avocados commonly ripen within one to two weeks, depending on the cultivar. Ethylene is also naturally released by ripening fruit, which explains why placing an avocado near apples or bananas can speed the process. Carbon dioxide and nitrogen may be used in food-storage atmospheres, but they are not the ripening signal identified here; helium is not the standard supermarket treatment.

The commercial use of ethylene ripening rooms was pioneered in the 1980s by California farmer Gil Henry. The method responded to shoppers squeezing hard avocados and rejecting them. Today, controlled ripening helps coordinate harvesting, shipping, and retail timing while reducing the chance that customers encounter only unripe fruit.